I use a Session variable called Session("UserName") to store a users username. When I set this variable and the close the browser window, the session is only supposed to end when when the session times out, Right? (20 minutes)

Why then when I open the browser again, before 20 min, is that session varaible lost? I have checked and the sessionID stays the same if I open and close the browser. Nowhere in my pages do I clear the variable, and nowhere do I call the session.abandon method???

Any explanations??